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Sundowning: severe dementia and bringing on the night (corticosterone increases aggression in the rat)

John H. johnh at faraway.xxx
Wed Apr 2 09:48:12 EST 2003

3/04/03 12:46am

J Neuroendocrinol 2000 Oct;12(10):937-40Related Articles, Ultradian
corticosterone rhythm and the propensity to behave aggressively in male

Haller J, Halasz J, Mikics E, Kruk MR, Makara GB.

Institute of Experimental Medicine, Budapest, Hungary. haller at koki.hu

Ultradian fluctuations in plasma glucocorticoids have been demonstrated in a
variety of species including humans. The significance of such rhythms is
poorly known, although disorganized ultradian glucocorticoid rhythms have
been associated with behavioural disorders. Here we report that ultradian
glucocorticoid rhythms may establish the propensity to behave aggressively
in male rats. Male rats were significantly more aggressive in the increasing
phase of their corticosterone fluctuation when confronting a male intruder
than counterparts in the decreasing phase of their corticosterone
fluctuations facing such opponents. Corticosterone fluctuations were
mimicked by a combination of treatments with the corticosterone synthesis
inhibitor metyrapone and corticosterone. Again, males with increased plasma
corticosterone levels were more aggressive than counterparts with a
decreased plasma corticosterone concentration. These data suggest that the
behavioural response to an aggressive challenge may vary in the same animal
across the day due to the pulsating nature of corticosterone secretion.
Aggressive behaviour is also episodic in humans; moreover, intermittent
explosive behaviour is recognized as a psychological disorder. It can be
hypothesized that a temporal coincidence between the occurrence of a
challenge and a surge in plasma corticosterone concentration may be one of
the factors that promote episodic aggressive outbursts.

PMID: 11012834 [PubMed - indexed for MEDLINE]

"Dag Stenberg" <dag.stenberg at nospam.helsinki.fi.invalid> wrote in message
news:b6egod$62b$1 at oravannahka.helsinki.fi...
> In bionet.neuroscience BilZ0r <BilZ0r at takethisouthotmail.com> wrote:
> (About Ken P Collins' AoK)
> > I've been idling in the newgroup for some time, and I keep seeing you
> > this terminology. (TD E/I, AoK, Ap8).  I'm a pharmacologist, (although
> > done a lot of neurosciency papers) and I'm just bout to start my
> > but I've never come across those ... Acronyms? Are they standard or just
> > something you made up?
> These are KPC:s abbreviations of a theory he designed himself. The AoK
> (Automation of Knowing) is a DOS-based hyperbase document comprising in
> form 1.18 Mb of disk space. Ap8 etc. refer to chapters in this
> hypertext. TD E/I is a quantity which is crucial to the theory.
> To my knowledge KPC has not really received any support from scientists
> for his theory. AoK has consequently not been published in the
> conventional way, but I am sure Ken would email you a copy if you are
> interested in looking at it seriously.
> Dag Stenberg

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